drm/i915: Only emit a flush request on the active ring.

When flushing the GPU domains,we emit a flush on *both* rings, even
though they share a unified cache. Only emit the flush on the currently
active ring.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --cc drivers/gpu/drm/i915/i915_drv.h
Simple merge

diff --cc drivers/gpu/drm/i915/i915_gem.c
Simple merge

diff --cc drivers/gpu/drm/i915/intel_ringbuffer.c
Simple merge

diff --cc drivers/gpu/drm/i915/intel_ringbuffer.h
Simple merge